Inverse Suspension Polymerization of Superabsorbent Polymer Hydrogels for Internally Cured Concrete
Abstract
Internal curing agents provide high performance concrete (HPC) with an internal source of hydration during curing to mitigate shrinkage and increase strength. Superabsorbent polymer (SAP) hydrogels have proven to be effective internal curing agents because of their ability to absorb and release large amounts of water. In this study, inverse suspension polymerization is used to synthesize spherical poly(sodium-acrylate acrylamide) hydrogels and determine their impact on internally cured mortar through microstructure analysis, autogenous shrinkage measurements and compression testing. The hydrogels were synthesized in-house with two concentrations of PANa (17 and 83 wt%). BSE images of cement paste segments confirmed that the hydrogels maintain their shape during mixing and the resulting voids are consistent with the hydrogel shape. Mortar containing these hydrogels showed a significant decrease in autogenous shrinkage. There was no change in the compressive strength of mortar when hydrogels were added despite the introduction of voids. This data was compared to a past study that used a solution polymerization technique to synthesize angular hydrogels. The spherical hydrogels improved cement hydration and reduced autogenous shrinkage compared to mortar containing angular hydrogels.
Degree
M.S.M.S.E.
Advisors
Erk, Purdue University.
Subject Area
Civil engineering|Materials science
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